From 32807462b08d420d666dfa8119953eabc1d57861 Mon Sep 17 00:00:00 2001
From: ThomasV <thomasv@electrum.org>
Date: Fri, 21 Mar 2025 11:15:43 +0100
Subject: [PATCH] qt: add warning about low utxo reserve

---
 electrum/gui/messages.py          |  5 +++++
 electrum/gui/qt/balance_dialog.py | 36 ++++++++++++++++++++++++++-----
 electrum/gui/qt/main_window.py    | 19 +++++++++-------
 3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/electrum/gui/messages.py b/electrum/gui/messages.py
index e10cae158..2b3c573ae 100644
--- a/electrum/gui/messages.py
+++ b/electrum/gui/messages.py
@@ -73,3 +73,8 @@ MSG_REVERSE_SWAP_FUNDING_MEMPOOL = (
     _("If you go offline before broadcasting the claiming transaction and let the swap time out, "
       "you will not get back the already pre-paid mining fees.")
 )
+
+MSG_LN_UTXO_RESERVE = (
+    _("You do not have enough on-chain funds to protect your Lightning channels.") + ' ' +
+    _("You should have at least {} on-chain in order to be able to sweep channel outputs.")
+)
diff --git a/electrum/gui/qt/balance_dialog.py b/electrum/gui/qt/balance_dialog.py
index b5f036796..b7d2a54ff 100644
--- a/electrum/gui/qt/balance_dialog.py
+++ b/electrum/gui/qt/balance_dialog.py
@@ -25,13 +25,14 @@
 
 from typing import TYPE_CHECKING
 
-from PyQt6.QtWidgets import QVBoxLayout, QLabel, QWidget, QGridLayout, QToolButton, QPushButton
+from PyQt6.QtWidgets import QVBoxLayout, QHBoxLayout, QLabel, QWidget, QGridLayout, QToolButton, QPushButton
 from PyQt6.QtCore import QRect, Qt
-from PyQt6.QtGui import QPen, QPainter
+from PyQt6.QtGui import QPen, QPainter, QPixmap
 
 from electrum.i18n import _
+from electrum.gui.messages import MSG_LN_UTXO_RESERVE
 
-from .util import Buttons, CloseButton, WindowModalDialog, ColorScheme, font_height, AmountLabel
+from .util import Buttons, CloseButton, WindowModalDialog, ColorScheme, font_height, AmountLabel, icon_path
 
 if TYPE_CHECKING:
     from .main_window import ElectrumWindow
@@ -102,8 +103,10 @@ class BalanceToolButton(QToolButton, PieChartObject):
         QToolButton.__init__(self)
         self._list = []
         self._update_size()
+        self._warning = False
 
-    def update_list(self, l):
+    def update_list(self, l, warning: bool):
+        self._warning = warning
         self._list = l
         self.update()
 
@@ -113,7 +116,14 @@ class BalanceToolButton(QToolButton, PieChartObject):
 
     def paintEvent(self, event):
         QToolButton.paintEvent(self, event)
-        PieChartObject.paintEvent(self, event)
+        if not self._warning:
+            PieChartObject.paintEvent(self, event)
+        else:
+            pixmap = QPixmap(icon_path("warning.png"))
+            qp = QPainter()
+            qp.begin(self)
+            qp.drawPixmap(self.R, pixmap)
+            qp.end()
 
     def resizeEvent(self, e):
         super().resizeEvent(e)
@@ -187,6 +197,22 @@ class BalanceDialog(WindowModalDialog):
         )
 
         vbox = QVBoxLayout()
+        if self.wallet.is_low_reserve():
+            reserve_str = self.config.format_amount_and_units(self.config.LN_UTXO_RESERVE)
+            hbox = QHBoxLayout()
+            msg = _('Warning') + ': ' + MSG_LN_UTXO_RESERVE.format(reserve_str)
+            label = QLabel(msg)
+            label.setWordWrap(True)
+            logo = QLabel('')
+            logo.setPixmap(
+                QPixmap(icon_path("warning.png")).scaledToWidth(
+                    25, mode=Qt.TransformationMode.SmoothTransformation)
+            )
+            logo.setMaximumWidth(28)
+            hbox.addWidget(logo)
+            hbox.addWidget(label)
+            vbox.addLayout(hbox)
+
         vbox.addWidget(piechart)
         grid = QGridLayout()
         #grid.addWidget(QLabel(_("Onchain") + ':'), 0, 1)
diff --git a/electrum/gui/qt/main_window.py b/electrum/gui/qt/main_window.py
index 181363e49..a73f4b4cc 100644
--- a/electrum/gui/qt/main_window.py
+++ b/electrum/gui/qt/main_window.py
@@ -1002,14 +1002,17 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger, QtEventListener):
             else:
                 network_text = _("Connected")
                 confirmed, unconfirmed, unmatured, frozen, lightning, f_lightning = self.wallet.get_balances_for_piechart()
-                self.balance_label.update_list([
-                    (_('Frozen'), COLOR_FROZEN, frozen),
-                    (_('Unmatured'), COLOR_UNMATURED, unmatured),
-                    (_('Unconfirmed'), COLOR_UNCONFIRMED, unconfirmed),
-                    (_('On-chain'), COLOR_CONFIRMED, confirmed),
-                    (_('Lightning'), COLOR_LIGHTNING, lightning),
-                    (_('Lightning frozen'), COLOR_FROZEN_LIGHTNING, f_lightning),
-                ])
+                self.balance_label.update_list(
+                    [
+                        (_('Frozen'), COLOR_FROZEN, frozen),
+                        (_('Unmatured'), COLOR_UNMATURED, unmatured),
+                        (_('Unconfirmed'), COLOR_UNCONFIRMED, unconfirmed),
+                        (_('On-chain'), COLOR_CONFIRMED, confirmed),
+                        (_('Lightning'), COLOR_LIGHTNING, lightning),
+                        (_('Lightning frozen'), COLOR_FROZEN_LIGHTNING, f_lightning),
+                    ],
+                    warning = self.wallet.is_low_reserve(),
+                )
                 balance = confirmed + unconfirmed + unmatured + frozen + lightning + f_lightning
                 balance_text =  _("Balance") + ": %s "%(self.format_amount_and_units(balance))
                 # append fiat balance and price